Bugs with benefits

Ever noticed a helicopter like graceful bug/insect with long colourful wings hovering near a pond, lake or river, moving excitedly forward and backwards? This is a dragonfly - one of the many aquatic insects that spend the first part of their lives- the larval stage in the water and devour tadpoles, mosquitoes and fish at rapid speeds. A grown up dragonfly is a lethal hunter as well and a single adult dragonfly can eat around 30 to 100 mosquitoes per day!

Another one that can be seen walking on water is interesting too! Water striders are small insects that are adapted for life on the top of still water and can be often seen walking on water!. They make use of the unique property of water where water molecules on the surface get attracted to each other and stay together.

The attraction between water molecules creates tension and a very delicate membrane. Water striders walk on this membrane. Water striders eat insects and larvae on the surface of water, such as mosquitoes and fallen dragonflies.

There are many such other interesting aquatic insects including springtails, mayflies, damselflies, stoneflies, alderflies, fishflies, dobsonflies, lacewings, beetles, giater bugs, ants and wasps, flies and mosquitoes, scorpion flies, moths, caddisflies which depend on freshwater such as rivers, lakes, streams  and ponds and spend a major part of their lives in water and then around the water.

Many of these insects have developed unique ways to survive and thrive in water and the surroundings and go through life stages like larvae, pupae, and adults. Some insects lay their eggs directly in the water, while others attach them to plants or other surfaces above the water. During the larval stages, many insects breathe underwater with their gills and have different ways of moving around, like swimming with their legs or tails, crawling, or even walking on the water.

Aquatic insects exist in a variety of forms according to their functions as surface skaters, burrowers, crawlers, and planktonic, divers, swimmers, clingers, sparklers, climbers, shredders, collectors, scrapers, piercers, predators, chewers, scavengers, filterers and carnivores!

Aquatic insects are declining

Read about the report here

Why is it crucial to save aquatic insects?

They play an important role in maintaining the health of water bodies

Aquatic insects play an important role in keeping water bodies clean as they help in processing, breaking down and decomposition of organic matter in the water bodies and in the recycling of nutrients. A higher number of aquatic insects can thus help in processing of large amounts of nutrients while a higher diversity of aquatic insects help in providing a variety of resources and ecosystem services and in effective use of all available resources in both space and time.

They help support the economy

Aquatic insects play a crucial role in supporting fisheries and aquaculture industries by serving as a food source for fish and other aquatic animals. This contributes to the livelihoods of fishermen and the overall economy of the fishing industry.

Dragonflies and damselflies help agriculture by controlling pests and preying on crop-damaging insects, reducing the need for chemical pesticides. This not only promotes environmentally friendly farming practices, but also help reduce costs that farmers may have to incur on pesticides.

They can be useful as indicators for assessing health of water bodies

The presence of certain aquatic insects can indicate the health of water bodies, which is important for industries such as agriculture, tourism, and fisheries that rely on clean water.

Aquatic insects are thus useful in biomonitoring and assessing the health of a water body as they are ubiquitous and sensitive to changes in aquatic habitats and environmental stressors. Their tendency to stick to a particcular locality over long periods can help in studying their responses to changes in their surrounding environments and help in effective determination of spatial extent of changes/disturbances in habitat. They are affected by the physical, chemical, and biological conditions of the water body.

They can play an important role in control of noxious weeds and mosquitoes

Several Invasive weeds in freshwater bodies are known to grow very fast and block the flow of the water, lead to eutrophication, out-compete native species and stop the flow of navigable waters and water-intake structures, and often kill fish and other organisms living in the waters. Recent evidence indicates that aquatic insects can have a great potential in helping to reduce or eliminate weeds. Some aquatic insects also play an important role in mosquito control as they devour mosquito larvae and eggs at fast speeds.

They can be useful in forensic entomology and biotechnology

The importance of aquatic insects in terms of forensic investigation can be very much useful in drowning cases like death due to submersion.

Some aquatic insects also have potential applications in biotechnology and pharmaceuticals, which can contribute to economic growth and development

They help in enhancing the appeal of recreational activities

Anglers come to areas abundant with aquatic insects because they serve as a natural food source for fish, leading to better fishing experiences. Additionally, the vibrant and diverse world of aquatic insects provides opportunities for nature enthusiasts to explore and appreciate the beauty of these ecosystems.

What can be done to conserve aquatic insects

Freshwaters support 6 percent of all known insect species and their survival is related to topography and the physical, chemical, biological, and geological processes that govern freshwater ecosystems, their flow regimes, seasonal patterns of fluctuations in water levels in water bodies, and vegetation both within the water and on the banks.

What needs to be done for aquatic insect conservation?

• Encouraging ecofriendly and nature based development models that replace unsustainable urbanisation and industrialisation patterns that destroy biodiversity.

• Deforestation is one of the major factors leading to biodiversity loss and insect decline. Regeneration of the forests is a need of the hour, since forests are the common home to all wild fauna including the insects. Removing alien and cryptic plant and tree species and replacing them with native plant species that attract insects is also crucial.

• Regulation of large-scale extension of agricultural activities and encouraging organic farming practices which support crop yield as well the biodiversity around and prevent the use of dangerous pesticides and chemicals that destroy the surrounding biodiversity.

• Implementing small farm ponds in the agricultural fields will aid in restoration of aquatic insect taxa like dragonflies and stoneflies.

• Public awareness is one of the key factors in conserving and managing the insect decline. Increasing public awareness through campaigns, seminars, conferences about the insect diversity and conservation and encouraging citizen science inititaives through collaboration and public participation in scientific research.

• Undertaking studies on diverse and ignored groups of insects such as Collembola, Ephemeroptera, Neuroptera, Plecoptera that play an important role in the providing a range of ecosystem services to humans and the environment.

• Monitoring of insect species, so that data should be utilised in the conservational strategies.

• Encourage research on the major aspects of insect decline which have not been adequately explored such as the impacts of industrial chemicals on insects, heavy metals, thermal biology etc.

• Increase funding opportunities for research and efforts made at surveying, monitoring, data analysis and laboratory studies on aquatic insects. Focus should be also given to insects which are becoming extinct

• Creating insect friendly habitats through catchment-wide conservation of freshwater ecosystems, maintaining connectivity and natural dynamics of freshwater ecosystems, protection of lakes, ponds and streams.

• Implementing nature based solutions through maintenance of artificial, shallow and well vegetated shorelines, maintenance of floodplains and retaining gravel bars

• Creating human-designed landscapes, which provide a great opportunity for aquatic insect conservation, including garden ponds, golf courses, and military training areas.

• Use of techniques such as DNA barcoding can act as a cost effective tool for quick and objective inputs to prioritise conservation efforts.